59: What is the difference between a mental image and a brain image?
A mental image is a private subjective experience which cannot
actually be directly observed. Mental images are the images that we
can picture inside our heads: by seeing real objects in front of us,
or by picturing the objects in our minds. This also incorporates the
noton of imagination, as we can also imagine images in our minds.
A mental image does not have to be visual, it can be created by any
one of our senses, or even by a mood or feeling. Any one of these
senses can conjure up an image in our minds which cannot be observed
by others.
Many theories of mental images are inadequate, since the only way they
can be explained is to refer to something inside the head looking at
them (ie. the homunculus )
Brain imaging is one method of explaining mental thought and
processes which does not incorporate the problem of the homunculus.
Common brain imaging techniques are PET and functional MRI; both of
which allow the brain to be directly observed through computer
scanning and X-rays. Brain images show increased blood flow during
mental effort and thought, due to increased chemical and electrical
activity. By looking at images of the brain, while subjects are
involved in certain thought tasks, the mental processes being
undertaken can be related to specific areas of the brain.
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